The manufacture of large metallic and composite material structures is generally very costly, not only because of the capital expense of the autoclaves and pressure vessels used in manufacture, but also because of the time and expense of operating such facilities.
It has, however, been necessary nonetheless to use the autoclaves and pressure vessels, because of the need to apply high, controllable temperature and pressure levels on the structures being molded or bonded. It would, of course, be preferable to make structures in some other fashion, both to reduce costs and to reduce the overall operating time consumed in bonding and curing operations.